casact / chainladder-python

Actuarial reserving in Python
https://chainladder-python.readthedocs.io/en/latest/
Mozilla Public License 2.0
186 stars 71 forks source link

[BUG] Trend no longer works correctly #525

Open jbogaardt opened 4 months ago

jbogaardt commented 4 months ago

Describe the bug I think a commit flipped start and end in the Triangle.trend method. However, nothing was done to correct the inputs of either the Trend estimator not CapeCod which uses the underlying triangle method, so I believe these are producing inaccurate results. I also think we shouldn't change behavior of existing methods without a formal deprecation. Users will likely have a variety of existing code that relies on the prior approach and they need a lead time to react to this change. I think this needs to be reverted.

Refer to commit https://github.com/casact/chainladder-python/commit/efde4a6492dfbf1c3115e2b5c0194cacdaaa6b81 for items to be reverted.